1. Technical Field
The present invention relates to liquid ejecting head units used in liquid ejecting apparatuses such as ink jet recording apparatuses and to liquid ejecting apparatuses, and particularly relates to liquid ejecting head units and liquid ejecting apparatuses in which a plurality of liquid ejecting heads can be attached to a head anchoring member in a removable state.
2. Related Art
A liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting a liquid as droplets, and that ejects various types of liquid from this liquid ejecting head. An image recording apparatus such as an ink jet recording apparatus (a printer) that includes an ink jet recording head (called simply a “recording head” hereinafter) and carries out recording by ejecting ink in liquid form through nozzles in the recording head as ink droplets can be given as an example of such a liquid ejecting apparatus. Meanwhile, in recent years, liquid ejecting apparatuses are being used in various types of manufacturing apparatuses, such as display manufacturing apparatuses, in addition to such image recording apparatuses. While a recording head in an image recording apparatus ejects ink in liquid form, a coloring material ejecting head in a display manufacturing apparatus ejects R (red), G (green), and B (blue) coloring material solutions. Likewise, an electrode material ejecting head in an electrode formation apparatus ejects an electrode material in liquid form, and a bioorganic matter ejecting head in a chip manufacturing apparatus ejects a bioorganic matter solution.
In recent years, there are, among such printers, printers that employ a configuration in which a single head unit is configured by arranging and anchoring a plurality of recording heads, each of which includes a plurality of nozzle rows formed by arranging a plurality of nozzles in rows, on a head anchoring member such as a sub-carriage or the like (that is, a multi-head type). In a configuration in which each recording head is positioned relative to the sub-carriage and is then screwed down onto the sub-carriage, the recording heads are temporarily anchored to the sub-carriage using an adhesive (for example, an instant adhesive) after being positioned and before being screwed down. As a result, it is possible to prevent the positions of the recording heads from shifting due to the rotational momentum occurring due to the screwing-down carried out in order to permanently anchor the recording heads using screws. When carrying out such temporary anchoring using an adhesive, however, it is difficult to remove the recording heads that have been anchored to the sub-carriage in order to repair or replace those recording heads. In response to such a problem, a configuration has been proposed in which an intermediate member called a “spacer” is provided between a recording head and a sub-carriage (for example, JP-A-2007-90327). According to this configuration, the recording head is first anchored to the spacer using screws, the spacer is then temporarily anchored to the sub-carriage using an adhesive, and then the spacer is permanently anchored to the sub-carriage using screws; accordingly, the recording head that has been anchored to the sub-carriage can be removed from the spacer and the sub-carriage by removing the screws between the recording head and the spacer. This makes it possible to remove the recording head with ease in order to replace or repair the recording head.
Incidentally, spacers employed in the aforementioned multi-head printers are formed as frame shapes that enclose the outer periphery of each recording head. Accordingly, when attaching each recording head to the sub-carriage, it has been necessary to provide a space between adjacent recording heads equivalent to the amount of space taken up by the spacers. For this reason, there has been a problem in that the dimension of the sub-carriage in the direction in which the heads are arranged is increased, which makes it difficult to reduce the size of the head unit, the printer, and so on.
In light of this issue, in recent years, a configuration has been proposed in which attachment portions such as flange portions or the like, to which spacers can be attached, are provided on both ends of each recording head in the direction that is orthogonal to the direction in which the recording heads are arranged, and two individual spacers that are smaller in size than past spacers are attached to the respective attachment portions. Through this, the intervals at which the recording heads are disposed on the sub-carriage can be reduced, which makes it possible to contribute to a reduction in the size of the head unit.
However, in the case where two spacers are used to attach a single recording head and the size of the spacers is reduced, the surface area where the recording head makes contact with the spacers is also reduced. Accordingly, there have been cases where recording heads have been tilted relative to the sub-carriage, particularly in cases where variations in the shapes, dimensions, and so on have occurred between the spacers on both ends.
It should be noted that this type of problem is not limited to ink jet recording apparatuses provided with recording heads that eject ink; the same problem can occur in other liquid ejecting head units, and liquid ejecting apparatuses provided therewith, that employ a configuration in which liquid ejecting heads are anchored to a head anchoring member such as the aforementioned sub-carriage with an intermediate member such as a spacer provided therebetween.